Decentralized neural identification and control for uncertain nonlinear systems: Application to planar robot

This paper presents a discrete-time decentralized neural identification and control for large-scale uncertain nonlinear systems, which is developed using recurrent high order neural networks (RHONN); the neural network learning algorithm uses an extended Kalman filter (EKF). The discrete-time control law proposed is based on block control and sliding mode techniques. The control algorithm is first simulated, and then implemented in real time for a two degree of freedom (DOF) planar robot.     

Influence of force-vector and force application plyometric training in young elite basketball players

Plyometric training composed by unilateral exercises with horizontal jumping direction seems to be an effective way to improve physical performance in athletes. The present study aimed to compare the influence of a combined jumping direction and force application (horizontal-unilateral vs. vertical-bilateral) plyometric training on linear sprinting, jumping, change of direction (COD) and dynamic balance in young elite basketball players. Twenty young (U-13 to U-14) male basketball players (age: 13.2?±?0.7 years, body mass: 59.5?±?12.7?kg, height: 172.9?±?7.9?cm) were randomly assigned either to a unilateral-horizontal (UH, n?=?10) or bilateral-vertical (BV, n?=?10) plyometric group, twice a week for 6-wk. Both groups performed between 60 and 100 jumps/session. UH executed all jumps unilaterally with horizontal direction, while jumps in the BV were bilaterally with vertical direction. Performance was assessed by a linear sprinting test, vertical and horizontal jumping tests, COD tests (V-cut and 5+5?m with a 180°COD test), an ankle dorsiflexion test and dynamic balance tests (anterior and postero-lateral directions). Within-group differences showed substantial improvements (Effect size (ES):0.31–1.01) in unilateral vertical and horizontal jumping, V-cut test and postero-lateral direction with right leg after both training interventions. Furthermore, UH group also substantially improved (ES:0.33–0.78) all sprinting times and postero-lateral direction with left leg, while BV enhanced anterior direction with left leg (ES:0.25). Between-group analyses showed substantially greater improvements (ES:0.33) in 10-m and V-cut test in UH than in BV. The likely beneficial effect (small ES) achieved in sprinting abilities suggests the combination of unilateral-horizontal jumps to improve such abilities.     

Bar velocities capable of optimising the muscle power in strength-power exercises

This study aimed at testing whether there are mean propulsive velocities (MPVs) capable of maximising the mean propulsive power (MPP) during the execution of bench press (BP), bench throw (BT), half squat (HS) and jump squat (JS). Additionally, we assessed the differences in MPP/MPV between ballistic and traditional exercises. Seventeen male rugby sevens players performed MPP tests in BP, BT, HS and JS and maximum isometric force (MIF) tests in HS and BP. The JS presented higher MPP (977.4 ± 156.2 W) than the HS (897.9 ± 157.7 W) (P < 0.05); the BP (743.4 ± 100.1 W) presented higher MPP than the BT (697.8 ± 70.4 W) (P < 0.05). Ballistic exercises presented higher optimum MPV (JS = 1.02 ± 0.07 m·s^?1; BT = 1.67 ± 0.15 m·s^?1) than traditional exercises (HS = 0.93 ± 0.08 m·s^?1; BP = 1.40 ± 0.13 m·s^?1) (P < 0.05). The optimum MPP in the JS, BT, HS and BP occurred at 28.2 ± 5.79, 23.3 ± 4.24, 32.4 ± 9.46 and 27.7 ± 5.33% of the MIF, respectively. The coefficient of variation (CV) of MPV at optimum MPP ranged from 7.4% to 9.7%, while the CV of %MIF ranged from 18.2% to 29.2%. The MPV is a more precise indicator of the optimum loads than the percentages of MIF due to its low inter-subject variability as expressed by CV. Therefore, MPV can be used to determine the optimum power load in the four investigated exercises.     

Performing in a multi-cultural context: The role of personality

Performance in situations where individuals from multiple countries are operating in a foreign culture is an underexplored domain of organizational behavior. We test hypothesized relationships between Big Five personality factors and dimensions of international performance using a sample of 232 international business students from 14 countries studying in Mexico. The results indicate differential relationships between personality factors and performance dimensions that emphasize interacting with host nationals and students from other countries, adjusting to a foreign environment, and maintaining a positive attitude in a foreign country. We discuss theoretical and practical implications for understanding and influencing performance in multi-cultural contexts.     

Are phonological processes the same or different in low literacy adults and children with or without reading disabilities?

The primary purpose of the study reported here was to examine whether phonological processes are the same or different in low literacy adults and children with or without reading disabilities in a consistent orthography. A sample of 150 subjects was selected and organized into four different groups: 53 low literacy adults, 29 reading disabled children, 27 younger normal readers at the same reading level as those with reading disabilities and low literacy adults, and 41 normal readers matched in age with the reading disabled group. We administered phonological awareness tasks which included items with different complexity of syllable structure. The results showed that the complexity of syllable structure had not a particularly marked effect on low literacy adults. Rather, the deletion task revealed the phonological deficit in low literacy adults across all syllable structures.     

Graphic design： A sustainable solution to manage the contents of teaching materials

There is a concern that the teaching of subjects is applied not only with support from a set of technological devices, but largely in the proper use of teaching and new technologies. Taking this idea, the authors develop a research and sustainable design that result in educational materials in solid content and technological innovation, also to have the benefit of learning process of a particular subject. The project is in its stage of development of educational materials, which indicates that only the experiment is missing.     

Learning-related shifts in generalization gradients for complex sounds

Learning to discriminate stimuli can alter how one distinguishes related stimuli. For instance, training an individual to differentiate between two stimuli along a single dimension can alter how that individual generalizes learned responses. In this study, we examined the persistence of shifts in generalization gradients after training with sounds. University students were trained to differentiate two sounds that varied along a complex acoustic dimension. The students were subsequently tested on their ability to recognize a sound that they had experienced during training when it was presented among several novel sounds varying along this same dimension. Peak shift was observed in Experiment 1, in which generalization tests immediately followed training, and in Experiment 2, in which the tests were delayed by 24 h. These findings further support the universality of generalization processes across species, modalities, and levels of stimulus complexity. They also raise new questions about the mechanisms underlying learning-related shifts in generalization gradients. The sound stimuli from this study are available as .wav files from http://lb.psychonomic-journals.org/content/supplemental.     

Quantitative analysis of Brazilian football players' organisation on the pitch

The purpose of this study was to characterise Brazilian teams' coverage area and spread on the pitch while attacking and defending and to analyse the teams' organisation in tackle and shot on goal situations. We obtained the trajectories of 223 players in eight games with a tracking method. Team area was defined as the area of the convex hull formed by players' positions. Team spread was defined as the Frobenius norm of the distance-between-player matrix. We calculated teams' area and spread over time and in situations of shots on goal (n = 233) and tackles (n = 1897). While the players attacked, spread and area (median +/- confidence interval) ranged from 322.9 +/- 0.8 to 387.8 +/- 1.0 m and from 905.4 +/- 4.4 to 1407.6 +/- 5.5 m2, respectively. On defence, the values were smaller (p < 0.05) and ranged from 283.4 +/- 0.9 to 325.8 +/- 0.9 m and from 773.8 +/- 4.6 to 1158.4 +/- 5.5 m2 for the spread and the area. In defending circumstances, the teams presented a greater area and spread when they suffered shots on goal than when the teams performed tackles. In attacking situations, the teams presented a greater area and spread when they suffered tackles than when they performed shots on goal. The results allowed showing the attacking-defending interaction between Brazilian teams.     

Scaled telerobotic control of a manipulator in real time with laser assistance for ADL tasks

In this paper we present a novel concept of shared autonomous and teleoperation control of a remote manipulator with a laser-based assistance in a hard real-time environment for people with disabilities to perform activities of daily living (ADL). The laser pointer enables the user to make high-level decisions, such as target object selection, and it enables the system to generate a trajectories and virtual constraints to be used for autonomous motion or scaled teleoperation. Autonomous, position-teleoperation and velocity-teleoperation control methods have been implemented in the control code. Scaling and virtual fixtures have been used in the teleoperation based control depending on the user preference.A real-time QNX operating system has been used to control a PUMA 560 robotic arm using a Phantom Omni master through a TCP/IP port. A SICK laser range finder was used to for the telerobotic control. The system was implemented with different control modes, and three healthy human subjects were trained to use the system for a pick-and-place task. Data were collected and presented for different control modes, and a comparison between these modes based on the time to complete the task was presented.     

Inverse optimal neural control of blood glucose level for type 1 diabetes mellitus patients

In this paper, inverse optimal neural control for trajectory tracking is applied to glycemic control of type 1 diabetes mellitus (T1DM) patients. The proposed control law calculates the adequate insulin delivery rate in order to prevent hyperglycemia and hypoglycemia levels in T1DM patients. Two models are used: (1) a nonlinear compartmental model in order to obtain type 1 diabetes mellitus virtual patient behavior, and (2) a neural model obtained from an on-line neural identifier, which uses a recurrent neural network, trained with the extended Kalman filter (EKF); the last one allows the applicability of an inverse optimal neural controller. The proposed algorithm is tuned to track a desired trajectory; this trajectory reproduces the glucose absorption of a healthy person. The applicability of the proposed control scheme is illustrated via simulations.